This invention relates to bag filling machines of the type including a hopper from which particulate material is dispensed in predetermined quantities or batches through a spout having a discharge end on which a bag is hung for filling. Such bag filling apparatus normally includes clamps carried on the spout and movable to a clamping position to hold a bag during the filling operation. See, for example, U.S. Pat. No. 4,078,358.
The present invention is particularly directed to bag filling apparatus of the aforesaid type having a clam shell type of discharge spout under a hopper, as disclosed in U.S. Pat. No. 4,322,932, having common inventorship herewith. One of the problems encountered with respect to such bag filling and handling apparatus is the creation of dust when particulate material is dumped into a bag from a hopper, through a discharge spout. If such dust is allowed to be released to the surrounding atmosphere, it can be deleterious to the health of persons working around the bag filling machinery. This is of course particularly so if the dust is at all toxic in nature.
Suction devices for removing air or trapped gasses from the interior of bags being filled are known. One such device is disclosed in U.S. Pat. No. 2,732,988 issued on Jan. 31, 1956 to Edward Feinstein. The Feinstein patent disclosed a suction pickup nozzle mounted on a reciprocal plunger which is moved downwardly into the mouth of the bag to discharge liquid into a bag. To the best of my knowledge and belief, no satisfactory means is known or has been developed for continuously and completely removing dust formed in the top of a bag during filling with particulate material. This is particularly true with respect to the use of so-called clamshell filling spouts which have a pair of closure members which are moved towards and away from each other to open and close the spout, with bags being clamped to the outside of the closure members during filling operations. Such filling spouts present particular dust control problems for particulate material.